ED-100A is an update of, and supersedes ED-100 of September 2000. It represents the minimum set of interoperability requirements and allocations necessary to provide adequate assurance that the elements of the communication, navigation, and surveillance/ air traffic management (CNS/ATM) system are compatible with each other and when operating together will perform their intended functions. These elements comprise the aircraft system, the air traffic service provider (ATSP) system, and the operator’s provisions to use the air traffic services, which may include third party or contracted communication services.